Method and device for controlling a hydrodynamic clutch

ABSTRACT

A method for controlling and filling a hydrodynamic clutch. A set variable can be preset for a variable which at least indirectly characterizes the functional state of the hydrodynamic clutch and which serves as an input variable of a control device assigned to the lubricant or operating material supply system. The control device comprises a pressure balance for controlling an adjusting device for influencing the operating material supply of the hydrodynamic clutch. The set variable can be preset in order to enable the adjustment of at least three basic functional states of the hydrodynamic clutch.

BACKGROUND OF THE INVENTION

The invention relates to a method for controlling a hydrodynamic clutchin a drive unit, an associated lubrication and operating material supplysystem, comprising an operating material source, a cooling device and astorage device.

Hydrodynamic clutches are known for many different applications. Amongothers, such hydrodynamic units are used as hydrodynamic clutches andhydrodynamic brakes. With regard to the constructive design options ofhydrodynamic machines as hydrodynamic clutches or brakes, reference ismade to “Voith: Hydrodynamic Gears, Clutches, Brakes. Otto KrausskopfVerlag GmbH, Mainz, 1970”. The disclosure content of said publication inthis connection is hereby fully incorporated into the disclosure contentof the present application.

Hydrodynamic clutches are known for example from the “VDI [Associationof German Engineers] Handbook of Gear Technology II”, VDI Guidelines VDI2153, Hydrodynamic Power Transfer Definitions—Designs—Methods ofOperation, whose disclosure content with regard to the design of suchunits is hereby fully incorporated into the present application.Clutches, especially when used in motor vehicles or in systems withhighly fluctuating operation, are engaged or disengaged by means offilling the working cycle with an operating fluid and by draining thebladed working cycle. In drive trains, a commonly useable lubricant andoperating material supply system is generally assigned to a plurality ofcomponents. For optimally meeting the requirements of the individualelements in the drive system, control devices are usually assigned tothe individual elements so as to ensure the respective operatingmaterial and lubricant supply. The technical control and regulation arevery complex.

Therefore, the objective of the invention is to develop a method forcontrolling a hydrodynamic clutch and also a device for controlling ahydrodynamic clutch such that with a minor effort for construction andtechnical control a secure and reliable method of operation is alwaysensured for the individual components, especially the hydrodynamicclutch. The individual possible functions should be easily adjustable.

The inventive solution to the problem is characterized by the featuresdescribed hereinafter.

SUMMARY OF THE INVENTION

According to the invention, in a drive system with at least onehydrodynamic clutch comprising at least two blade wheels that togetherform a toroidal working space to which at least one supply line and onedischarge line are assigned and to which a lubricant or operatingmaterial supply system is assigned, a set variable can be preset for avariable characterizing at least indirectly the functional state of thehydrodynamic clutch and which serves as an input variable of the controldevice assigned to the lubricant or operating material supply system forcontrolling an adjustment device for influencing the operating materialsupply of the hydrodynamic clutch such that at least three basicfunctional states of the hydrodynamic clutch can be set. Said states aredraining, filling and, depending on the type of the hydrodynamicelement, controlling the transferable moment.

At least three basic functional states can be set for the hydrodynamicclutch via the adjustment device for influencing the operating materialsupply of the hydrodynamic clutch, where in a first basic functionalstate the hydrodynamic clutch is disengaged, especially drained, whilein a second basic functional state the working space of the hydrodynamicclutch is supplied with operating material via an operating materialsource and in a closed circuit a portion of the operating material fromthe working space is resupplied to the working space via a coolingdevice, and in a third basic functional state, also called controlledstate, a portion of the operating material from the working space isresupplied to the working space via the cooling device and the leakageis compensated by means of a coupling to the operating material supplysource, where in said state the transferable moment can be varied inthat the fill factor is changed.

According to an especially advantageous embodiment, the method of theinvention is used for a hydrodynamic element in the form of ahydrodynamic clutch in a drive unit with an associated bridging clutch.The drive unit comprises a supply system for lubricant and/or operatingmaterial and/or control means and an optional storage device which isused both by a hydrodynamic clutch and a bridging clutch. In one basicfunctional state, the supply of the lubricant system of the drive systemis additionally adjustable, where the set variable for actuating theadjustment device is generated from the set value of the variablecharacterizing at least indirectly the functional state of thehydrodynamic clutch in dependence of a variable characterizing at leastindirectly the pressure in the discharge line of the hydrodynamicclutch.

By means of the adjustment device for influencing the operating materialsupply of the hydrodynamic clutch at least the three basic functionalstates of the hydrodynamic clutch listed below are adjustable, where

-   -   a) in a first basic functional state of the hydrodynamic clutch,        especially the draining or the drained element, operating        material from an operating supply source is supplied to the        lubricant connection of the drive unit via the cooling device;    -   b) in a second basic functional state the working space of the        hydrodynamic clutch is supplied with operating material from a        reservoir and from the operating material source and in a closed        circuit a portion of the operating material from the working        space is resupplied to the working space via the cooling device,        and    -   c) in a third basic functional state, also called controlled        state, a portion of the operating material from the working        space is resupplied to the working space via the cooling device,        and leakage is compensated by means of a coupling with the        operating material supply source.

In the third basic functional state, at least two boundary states areadvantageously differentiated, a first boundary state for high operatingpressures and a second boundary state for low pressures. The pressure inthe available control range is changed either stepwise or continuously.

In terms of technical equipment, the terms “supply line” and “dischargeline” should not necessarily be understood to be lines. They can also bepresent in the form of channels or another type of mechanism guiding theoperating material.

In the simplest case, the adjustment between the individual basicfunctional states takes place in a plurality of steps, butadvantageously also continuously.

The term lubricant supply systems combines the devices used to lubricateindividual components of the drive unit, for example the bearings.

The supply of the control means which may be provided relates toproviding the required operating forces for the bridging clutch by meansof hydraulics.

The method of the invention allows that an operating material orlubricant supply system which is used in common by the hydrodynamicclutch and the complete drive unit always ensures a safe and reliablemethod of operation for the individual components, especially thehydrodynamic clutch, with only a minor effort for the design andespecially for technical control, because a variable characterizing atleast indirectly the pressure in the discharge line of the hydrodynamicclutch, advantageously the pressure itself, is always taken intoconsideration.

According to a refinement of the method of the invention, additionalsteps are taken so as to ensure a reliable method of operation of thecomplete drive system. For example, additional valve devices areprovided for performing separate partial functions with priority or witha certain valence, including, for example,

-   -   a) giving priority to providing the primary pressure of the        hydrodynamic clutch;    -   b) permanent lubricant supply for the drive unit, for example        depending on the pressure or by means of volume control.

Advantageously, the hydrodynamic unit is a hydrodynamic clutchcomprising a pump wheel and a turbine wheel. An application inconnection with hydrodynamic converters is also conceivable. Anotherapplication is a hydrodynamic clutch with which optionally the functionof generating a braking moment and transferring high torques can beachieved, as described in PCT/EP97/06623 and PCT/EP97/06646, forexample. The disclosure content of said patents with regard toconstructive design, method of operation and control of a hydrodynamicclutch operated in such a way is hereby fully incorporated into thedisclosure content of the present application.

The hydrodynamic clutch comprises at least two blade wheels thattogether form a toroidal working space. Theoretically, it is alsopossible to use the method of the invention for hydrodynamic units thathave multiple working spaces, for example duplex clutches.

In terms of equipment, such functions are handled by means of a controldevice which is assigned to a lubricant and operating material supplysystem of the hydrodynamic clutch. When the hydrodynamic clutch is usedin a drive unit, the control device is advantageously assigned to thelubricant or operating material supply system used in common by thehydrodynamic element and the bridging clutch.

Using one single or commonly useable control device offers the advantageof a central arrangement for supplying multiple systems. Itadvantageously comprises a pressure balance, i.e. the functionalprinciple is based on compensating the force of pressure acting on aplunger of known cross-sectional area or the sealing liquid in a ringpipe by means of a counter-force, where a balance of forces is achievedin that the plunger is moved, for example. The force of pressure and thecounter-force are a force of pressure corresponding to the preset valuefor a desired functional state of the hydrodynamic clutch, which can bedescribed by the size of the area of application in the pressure balanceand a pressure generated by means of a proportional valve, for example,and a force characterized by the pressure in the discharge line of thehydrodynamic clutch and the associated area of application in thepressure balance.

The control device has a housing in which at least one control boring isworked in. As viewed over its axial extension, the control boringadvantageously has varying diameters forming separate control chambersthat can be coupled to connections. However, designs with angularchambers are also conceivable. In the control boring, at least onecontrol plunger is disposed which can be moved in an axial direction andwhich advantageously also has varying diameters over its axialextension. The individual partial sections with varying diameter, orwith varying dimensions in the case of an angular design, on the controlplunger and the control boring form the so-called control edges.

The areas with varying outside diameter or varying outside dimensions ofthe control plunger can be disposed so as to alternate. The controlplunger is advantageously designed such that as viewed over its axiallength, it has only two different diameters, a first diameter which issmaller than the diameter of the control boring, and a second diameter,which substantially corresponds to the diameter of the control boringtaking into account the required tolerances. In accordance with theposition of the control plunger, especially the control edges in thecontrol boring, the individual connections are at least partially orfully uncovered or covered as a result of which the individualfunctional states of the hydrodynamic clutch are achieved, and when usedin driving units, the function of supplying the lubricant system of thedrive unit is possibly achieved in addition. At least the followingindividual connections should be provided:

Connection 1—operating material supply source and cooling deviceConnection 2—reservoir Connection 3—supply line of the hydrodynamicclutch Connection 4—discharge line of the hydrodynamic clutch Connection5—cooling device Connection 6—lubricant line for the drive unit

The embodiment used for drive units is described below.

The input variable is a set variable for a variable characterizing atleast indirectly the functional state of the hydrodynamic clutch. It canbe preset in the form of a signal for putting into operation the elementembodied by the hydrodynamic clutch, for example, from which a setvariable is formed for actuating an adjustment device for influencingthe operating material supply of the hydrodynamic clutch.

When the control device is embodied by a pressure balance the controlplunger acts as an adjustment device. The set variable is the forceacting on the control plunger. The other input variable is formed by thepressure in the discharge line of the hydrodynamic clutch or by thepressure on an outlet from the working space.

The pressure balance represents a simple, cost-effective and compactcontrol device. In order to provide a universal unit, additional valvedevices for a variety of different functions are advantageouslyintegrated in the control device, for example for the volume control ofthe lubricant supply regardless of the pressures that are present in thesystem. The valve devices are advantageously combined into units thatcan be disposed in the control boring of the pressure balance, whichprovides an especially compact control device.

When the method is used only for a hydrodynamic clutch for controllingthe operating material supply from an operating material supply systemassigned only to said clutch, the pressure balance is provided at leastwith the connections to the operating material supply source and thecooling device, with one connection for the supply line and one for thedischarge line of the hydrodynamic clutch. In this case, the controlplunger of the pressure balance is also actuated by a force formed froma variable characterizing at least indirectly the desired set state ofthe hydrodynamic clutch and additionally by a counter-acting forceformed by the pressure in the discharge line. This always ensuresfeedback between the desired set state and the actually set state.

BRIEF DESCRIPTION OF THE DRAWINGS

The solution of the invention is explained below by means of thedrawings, as follows:

FIGS. 1 a-1 d show a section of a lubricant or operating material supplysystem with a control system according to the invention for ahydrodynamic clutch;

FIGS. 2 a-2 b is a general block diagram of the control of theinvention;

FIG. 2 c is a block diagram of the control of the invention for ahydrodynamic clutch with its own operating material supply system;

FIG. 3 is an embodiment of a control device configured in accordancewith the invention in the form of a pressure balance;

FIG. 4 shows the positions of the control plunger of the pressurebalance of FIG. 3 in the functional states of the hydrodynamic clutchdescribed under FIGS. 1 a-1 d;

FIG. 5 is an embodiment of a lubricant or operating material supplysystem with volume control;

FIGS. 6 a-6 b illustrate, each by means of a section of a pressurebalance with varying configurations of the control plunger, thearrangement of the valve devices required for achieving a permanentlubricant supply;

FIGS. 7 a-7 b illustrate, each by means of a section of a pressurebalance of varying configuration the arrangement of the valve devicesintegrated in the connecting lines between the reservoir and thepressure balance, or between the reservoir and the lubricant supplyline;

FIG. 8 illustrates, by means of a control diagram according to FIG. 1 aa simplified lubricant or operating material supply system with theinventive control of a hydrodynamic clutch;

FIGS. 9 a and 9 b illustrate the individual functional positions of thepressure balance for an embodiment in accordance with FIG. 8.

DETAILED DESCRIPTION

FIGS. 1 a to 1 d are schematically simplified illustrations by mean of ahydraulics plan of a section of a drive system 1 with a drive unit 100comprising at least one hydrodynamic element 2, in the present case ahydrodynamic clutch 5, a bridging clutch 3 and a lubricant or operatingmaterial supply system 4. The hydrodynamic clutch comprises at least onerotor blade wheel and one stator blade wheel (not shown) which togetherform a toroidal working space. A guide wheel for changing thetransmitting behavior by means of changing the swirl is not provided,i.e. the clutch has no guide wheel. The drive unit with the hydrodynamicclutch 5 can be disposed in front of or inside the transmission. Thehydrodynamic clutch 5 is then located on the driving side of thetransmission. The lubricant or operating material supply system 4comprises an operating material source 6, in the present case in theform of an oil sump, from which by means of a pumping device, in thepresent case a gear pump 7, the oil is supplied to the respective linesystems for supplying the individual elements—the hydrodynamic clutch 5and/or the drive unit 100.

According to the invention, a control device 8 is assigned to thehydrodynamic clutch 5, which, in addition to controlling a variablecharacterizing at least indirectly the functional state of thehydrodynamic clutch 5, preferably the fill factor, realizes or controlsvarious supply functions of the lubricant system 9 of the complete driveunit 100, for example. The control device 8 for controlling a variablecharacterizing at least indirectly the functional state of thehydrodynamic clutch 5 is preferably configured as a pressure balance 10.

The functional principle is based on compensating the force of pressureacting on a plunger of known cross-sectional area or on the sealingfluid in a ring pipe by means of a counter-force, where a balance offorces is achieved in that the plunger is moved, for example. To thisaim, a set variable for a variable characterizing at least indirectlythe functional state of the hydrodynamic clutch can be preset whichserves as an input variable of a control device 8 assigned to theassociated lubricant or operating material supply system 4 forcontrolling an adjustment device for influencing the operating materialsupply of the hydrodynamic clutch 5 and the lubricant supply 9 of thecomplete drive unit 100. Said set variable for actuating the adjustmentdevice is then generated from the set value of the variablecharacterizing at least indirectly the functional state of thehydrodynamic clutch in dependence of a variable characterizing at leastindirectly the pressure in a discharge line 32 of the hydrodynamicclutch 5.

By means of the pressure balance 10, at least three, preferably fourbasic functional states of the hydrodynamic clutch 5 can be set, but theadjustment is advantageously continuous. With regard to the design ofthe pressure balance 10, reference is made to FIGS. 3 and 4.

In a first functional state of the hydrodynamic clutch 5, operatingmaterial is supplied from the operating material source 6 via a coolingdevice 11 into the lubricant system 9 of the drive unit 100. Saidfunctional state is illustrated in FIG. 1 a. The operating material, forwhich oil is used above all, flows from the oil sump 6 via line 13 intothe adjoining line section 14, the cooling device 11 and line 18 intothe lubrication line 15 which is coupled to the lubricant connections ofthe lubricant supply system 9 of the drive unit 100. In said functionalstate, the hydrodynamic clutch 5 is completely empty, and no operatingmaterial is supplied to the toroidal working space. The disengaged stateof the hydrodynamic clutch 5 corresponds to the first functional state.In said state, no torque is transmitted, and the operating material isrequired merely for lubricating the individual elements of the driveunit 100. In the lubrication line 15, a back-pressure valve R5 isadvantageously disposed so as to prevent the operating material fromflowing back from the lubrication line 15.

The lubricant or operating material supply system used by the drive unit100, i.e. by the hydrodynamic clutch 5 and the bridging clutch 3, alsosupplies the bridging clutch 3 with the required control pressure. Inthe illustrated case in FIG. 1 a, the supply line 25.1 is coupleddirectly to the principal supply line 26 that connects the pumpingdevice, in the present case the gear pump 7, with line 13.

A reservoir 27 is assigned to the hydrodynamic clutch 5. The reservoir27 is preferably air-operated. To this aim, a valve 28 is assigned tothe reservoir 27. Said valve is enabled only briefly for purposes offilling the hydrodynamic element, especially the hydrodynamic clutch 5,and then it is disabled.

The state of putting the hydrodynamic clutch 5 into operation, theso-called filling phase, can be described by the line connectionsillustrated or realized by means of the pressure balance 10 in FIG. 1 b.The filling process substantially takes place via the reservoir 27 whichcan be coupled via line 19 with the supply line 30 by means of thepressure balance 10.

A valve device in the form of a back-pressure valve R2 is thenpreferably provided in line 19 so as to prevent that the operatingmaterial will flow back from the hydrodynamic clutch into the reservoir27 in the event that the filling resistance becomes greater than theavailable push-in pressure applied by means of the valve device 28. Thecoupling between the pressure balance and the reservoir is realized viaa line 16. Furthermore, line 16 is connected to the lubrication line 15of the drive unit 100. In order to prevent that the stored volume ispushed out into the lubrication line 15 and thus into the lubricantsystem of the drive unit 100, a valve device, for example theback-pressure valve R1, is provided in the connecting line between thereservoir and line 16. In addition to the filling via the reservoir 27,operating material is supplied via the operating material source 6. Theoperating material flows from the principal line 26 into the connectingline 13 to line 14 which is coupled to the cooler. The operatingmaterial then flows via line 14, the coupling between line 14 and line20, which is coupled to the supply line 30 of the hydrodynamic clutch,into the hydrodynamic clutch 5. In addition, operating material issupplied from the reservoir 27 into the connection between line 14 andline 20, which is realized by means of the pressure balance 10, in thatline 19 is also coupled to line 20. As a result of the pressuredifferences arising in the hydrodynamic clutch, operating materialenters line 21 via the discharge line 32 and is supplied as a result ofthe position or positions of the pressure balance 10 characterizing saidfunctional state into the connecting line to the cooler 11 and to line14 via said cooler so as to be resupplied to the hydrodynamic clutch 5.Therefore, during the filling phase a closed cooling circuit is alreadyformed between the discharge line 32 of the hydrodynamic clutch 5 andthe supply line 30. Said closed circuit can also be called coolingcircuit and is identified by 33 in the present case. Therefore, thecooling circuit 33 is coupled to line 13 and thus to the supply linefrom the operating material source 6 to the hydrodynamic clutch, where,as shown in the present case, common lines are advantageously used, inthe present case a section of line 14.The flow of operating material used for cooling, i.e. the coolingcircuit 33 which is formed in addition to the working cycle in theworking space of the hydrodynamic clutch, is characterized by a changein the direction of the flow of operating material relative to the flowof the operating material or lubricant in the first functional state ofthe hydrodynamic clutch.

When actuated by means of compressed air the reservoir 27 has areservoir plunger 101, for example, which is coupled to the valve device28 and therefore one side of the plunger is actuated by compressed air.On the other side of the reservoir plunger 101, there is operatingmaterial which is pushed into the clutch 5. Although a sealing device isprovided, operating material may collect on the air-actuated side of theplunger 101 after a certain operating time and result in the risk thatsuch operating material will be discharged into the open via theaeration of the valve 28. In order to prevent this, the leaking oil canbe removed by specifically discharging it. The air-actuated side of theplunger then forms an oil chamber that accommodates a certain volume ofleakage oil, which can be discharged via a discharge opening in the oilchamber, for example. Another option is the automatic removal of thecollected operating material. In this case, a connecting line to thedrive unit 100 is assigned to the air channel for actuating the plunger,i.e. the coupling between the reservoir 27 and the valve device 28,where a ball valve device is disposed in the drive unit 100, forexample. As soon as the collected operating material exceeds the levelof the ball vale, operating material is blown briefly from the air sideof the reservoir 27 into the drive unit 100 with every actuation. Saideffect is generated in that the valve seat is opened by the ball as aresult of gravity when the pneumatic valve 28 is disengaged. When thepneumatic valve 28 is engaged, the valve seat is closed by the suddenflow of air. Between the functional states of the ball valve with openand with closed valve seat, a certain amount of operating materialbriefly flows from the air-actuated side of the plunger to the side ofthe drive unit. Said amount of operating material is determined by thelength of the path, the obliqueness of the valve seat and the layout ofthe cross-sections of flow and must safely exceed the maximum amount ofleakage so as to ensure that no operating material will exit via thepneumatic valve 28.

A further third functional state of the hydrodynamic clutch 5 can bedescribed by the position of the pressure balance 10 and the connectionsthus realized between the individual lines, as illustrated in FIG. 1 c.Said functional state describes the controlled state of the hydrodynamicclutch 5. Lines 14 and 20 are coupled together and thus to the supplyline 30 of the hydrodynamic clutch 5. The pressure in channel 14approximates the inflow resistance in line 20. The pumping device in theform of the gear pump 7 merely resupplies the amount of leakage of thehydrodynamic clutch. Excess operating material supplied by the pumpingdevice, especially the gear pump 7, flows from line 14 to the linesection 16 and from there into the lubricant line 15 to the lubricantconnections 22 to 24. The coupling between the supply line 30 of theclutch and the reservoir 27 is disconnected. Because of the pressuredifferences arising in the clutch 5, a cooling circuit 33 is alsogenerated in this case, where the coolant flows from the discharge line32 into the connecting line 18 to the cooling device 11 and afterpassing the cooling device 11, it is supplied to the supply line 14 andinto the supply line 30 of the hydrodynamic clutch.

If there is any excess operating material, a portion thereof is guidedvia line 16 into the lubricant system 9 of the drive unit 100. Saidthird functional state can be divided further into a fourth functionalstate which is required for setting very low pressures, i.e. forgenerating a low transmission moment. In said functional state, thesupply pressure is lowered below the level of the pressure in line 16.

With regard to the individual positions of the control valve of thepressure balance 10 for realizing the individual functional states,please see FIGS. 4 a to 4 d which will be described below.

The function of the control device 8 according to FIGS. 1 a to 1 d isillustrated in the form of a block diagram in FIG. 2 a. Accordingly, thecontrol device 8 has at least one input 40 and six outputs 41 to 46. Theinput 40 can be coupled to a device 47 for presetting a set value for avariable characterizing at least indirectly the functional state of thehydrodynamic clutch. According to the preset value, the control device 8forms set variables, in the present case the individual set variables Y1to Y6, for setting the desired functional state. Forming the setvariables takes into consideration the aspect under which the operatingmaterial or lubricant supply system is not only assigned to thehydrodynamic clutch, it is also responsible for respectively supplyingthe bridging clutch and the other elements of the drive unit withlubricant or the respective control pressure. Specifically, this meansthat the respective couplings between supply, discharge, cooling device,operating material source, lubricant system and reservoir have to berealized in accordance with the formed set variables.

This can take place via a plurality of valve devices, for example, whichare disposed accordingly in the commonly used line system. A preferred,especially advantageous embodiment of the control system is illustratedschematically simplified in FIGS. 1 a to 1 d. The block diagram for saiddevice is found in FIG. 2 b. The so-called control pressure p_(r) servesas the input variable of the control device 8 which is embodied by apressure balance 10. The control pressure acts on the plunger area of aso-called control plunger which acts as a transfer link 49. Other inputvariables are the force F₄ applied by means of an energy storage unit48, for example in the form of a spring-type storage device, and thepressure p₃₂ prevailing in the discharge line 32 of the hydrodynamicclutch 5. From said input variables, an output variable is produced forthe movement of the control plunger 49 and thus the control edgesrelative to the individual line connections by the path □s. Therespective position of the control plunger 49 then determines thefunctional states of the hydrodynamic clutch as a result of the couplingbetween individual line sections or lines. The actual constructiveembodiment of the pressure balance 10 is described by means of anexample in FIG. 3.

FIG. 3 is a sectional view illustrating an option of the constructiveembodiment of the pressure balance 10 used as a control device 8according to the invention. It comprises a housing 56 in which at leastone control boring 57 is provided. Said control boring 57, as viewedover its axial extension, has varying diameters that form individualcontrol chambers identified by 19.1, 14.1, 20 e.1, 21.1, 18.1, 16.1 and14.1 in accordance with the connections. In the control boring 57, acontrol plunger 49 is disposed which can be moved in an axial directionand which has varying diameters over its axial extension.

Together, the individual partial sections with varying diameter formcontrol edges. In the present case, said control edges are identified by60, 61, 62, 63, 64, 65, 53, 67 and 68.

The areas of varying outside diameter of the control plunger 49 arealternating. The control plunger is advantageously configured such that,as viewed over its axial length, it merely has two different diameters,a first diameter D1, which is smaller than the diameter D3 of thecontrol boring. The second diameter D2 of the control plunger 49substantially corresponds to the diameter D3 of the control boring 57taking into account the respective tolerances required for realizing anaxial movement of the control plunger 49 in the control boring 57. Basedon the position of the control plunger 49, especially the control edgesin the control boring 57, the individual connections are at leastpartially or fully uncovered or covered, thereby achieving theindividual functional states of the hydrodynamic clutch 5 and thefunction of supplying the lubricant system of the complete drive unit100. The individual connections are assigned to the respective lines inthe lubricant system as follows:

1^(st) connection 14—lubricant supply source 6 and cooling device 112^(nd) connection 19—reservoir 27 3^(rd) connection 20—supply line 30 ofthe hydrodynarnic clutch 5 4^(th) connection 21—discharge line 32 of thehydrodynamic clutch 5 5^(th) connection 18—cooling device 11 6^(th)connection 16—lubricant line 15

The respective identifications of the connections correspond to the lineidentifications shown in FIG. 1. Furthermore, another connection isprovided for the control pressure pR, which acts upon the area 50 of thecontrol plunger 49. In order to realize the function of the pressurebalance, a counter-force is assigned to the force directed at the area50 by means of the pressure pR, which consists of the force of aspring-type storage device 48 and the force formed in the discharge line21 to the piston area 53 as a result of the pressure prevailing in thedischarge line 32 of the hydrodynamic clutch. The spring-type storagedevice 48 is disposed in a respective boring 51 in the control plunger49. The spring is supported by the inside boring surface 52 of theboring 51 in the control plunger 49.

As illustrated in the present case, the control plunger isadvantageously configured in two parts comprising a first part 49.1 anda second part 49.2. This is advantageous in that the control boring canbe produced more efficiently by approaching it from two sides.

For the embodiment of the pressure balance shown in FIG. 3, FIGS. 4 a to4 d illustrate the individual functional states, as described for FIGS.1 a to 1 d, by means of the positions of the control edges in thecontrol boring 57. FIG. 4 a illustrates the first functional state inwhich the hydrodynamic clutch is not in operation, i.e. it isdisengaged. In said state, the discharge line 32 is connected via line21 and thus the connection 21 with the relief device E. Furthermore, viathe connection 16, lubricant or operating material is supplied from theoperating material source 6 into the lubricant line 15, which is whyconnection 18 is in flow connection with connection 16 in said state.Therefore, the flow of operating material is merely guided via thecooling device into the lubricant line 15, as already described underFIG. 1 a.

FIG. 4 b illustrates the position of the control plunger 49 for thesecond functional state of the hydrodynamic clutch. Said area is alsocalled the area where the hydrodynamic clutch is put into operation orthe filling phase. The filling advantageously takes place via thereservoir 27 and thus via lines or connections 19 and 20 andadditionally via line or connection 14 from the operating materialsource to line 20 which is coupled to the supply line 30. Therefore, asshown in FIG. 4 b, the operating material can enter connection 20 fromconnection 19. According to said functional method, the discharge line32 of the hydrodynamic clutch 5, which is coupled to connection 21, isin flow connection with connection 18, which is coupled to the coolingdevice 11. The two connections 16 and 14 which are located outside in anaxial direction are locked.

FIG. 4 c illustrates the position of the control plunger 49 in thecontrolled state of the hydrodynamic clutch, where the control plungerwith the control edge 64 leaves the lock between the connections 14 and16. A flow connection exists between connections 14 and 20 and between21 and 18 so as to realize a cooling circuit, where the working space ofthe hydrodynamic clutch or the supply line 30 is supplied via thecoupling of connections 14 and 20. The coupling to the reservoir,especially the coupling between connections 19 and 14, is disconnected.Therefore, the hydrodynamic clutch 5 is supplied only with the operatingmaterial from the reservoir, which is required to achieve a controlledstate. The controlled state or the beginning of said controlled state isthen characterized by the overlapping of the control edge 64 and therespective control edge in the control boring 57 between connections 16and 14.

The area of the controlled state can be further limited by the positionof the control plunger 49 shown in FIG. 4 d. While the filling phase ofthe hydrodynamic clutch 5 is characterized in that the control plunger49 moves in an axial direction in the direction of the control pressurepR that acts on the control plunger area 50, the control plunger 49 inthe controlled state moves in an axial direction opposite the activedirection of the control pressure pR. The two boundary positionsdescribing the area of the controlled state are shown in FIGS. 4 c and 4d. The second boundary or controlled position shown in FIG. 4 d ischaracterized in that the control edge 62 of the control plunger 49assumes the end position in which the relief line is connected to theconnecting line 21, and thus to the discharge line 32 of thehydrodynamic clutch 5. Over the complete controlled state, however, theoperating material circulates from the discharge line 32 of thehydrodynamic clutch to the cooling device via line 21 to connection 18and after passing the cooling device again to the supply line 30 of thehydrodynamic clutch via the line or connections 14 and 20. Furthermore,shortly after achieving the controlled state, the supply of operatingmaterial to the lubricant line 15 of the drive unit 100 is realized.

The control device 8, especially the pressure balance 10, which iscontrolled via a control pressure pR, set by means of a proportionalvalve 70, as shown in FIGS. 1 a to 1 d, for example, allows that theindividual line sections or the individual lines are coupled together soas to bring the hydrodynamic clutch 5 into the respective functionalstates. Furthermore, means are assigned to the commonly used lubricantor operating material supply system which cooperate with the controldevice 8 and give priority to performing certain functions in theoperating material or lubricant supply system.

In accordance with the function to be performed, said means can vary indesign and configuration. In FIGS. 1 a to 1 d, the valves VLB1 and VLB2as well as R5 are disposed so as to prevent breakdowns in thelubricating oil supply of the drive unit 100 during the functional stateFILLING or the controlled state. The valve device VLB2, which isdisposed in the connecting line between the principal connecting linebetween the oil sump 6 and line 14, is a pressure control valve. Thevalve device VLB1, disposed in a connecting line between the lubricatingoil line and the principal line 13, is a pressure reducing valve. Thevalve device R5 is a back-pressure valve. When the pressure in thelubricating oil line 15 drops below a certain level, the valve deviceVLB1, i.e. the pressure reducing valve, connects the principal line 13and therefore the operating material supply source with the lubricatingline 15. The hydrodynamic clutch is then in a bypass with respect to theoperating material supply. The functional state achieved by thehydrodynamic clutch is irrelevant. The valve device VLB2 generates aslight pressure back-up so as to allow the necessary flow of lubricatingoil from the principal line 13 via VLB1 to the lubricating line 15.

While the embodiment according to FIGS. 1 a to 1 d with the valves VLB1and VLB2 always ensures a certain pressure in the lubricating system ofthe drive unit during operation, FIG. 5 illustrates another option ofsupplying the lubrication system of the drive unit 100 via a volumecontroller that supplies a certain amount of oil, which can be set via athrottle or a spring, into the lubrication system 15 regardless of theprevailing pressure conditions. The valve devices VLB1 and VLB2 are thenreplaced by the valve device VLB.

Another alternative for the structural configuration of the operatingmaterial or lubricant supply system 4 ensuring the lubrication of thedrive unit 100 while being filled is illustrated in FIG. 1 d. The basicdesign of the overall system consisting of the hydrodynamic clutch 5,the drive unit 100 and the bridging clutch 3, but not including thevalve devices VLB1 and VLB2, corresponds to the one described underFIGS. 1 a-1 d. Therefore, the same identifications are used foridentical elements. A minimal lubricant supply which can be set by meansof a throttle D8, or alternatively by means of a spring, is then ensuredin the lubricant supply system 15 regardless of the existing pressures.Furthermore, in order to realize said function, a back-pressure valve R6is provided. The throttle D8 and the back-pressure valve R6 are disposedin a connecting line 100 between the lubricant supply line 15 and theconnecting line 8 from the proportional valve 70 for presetting a setvalue or generating a set value signal in the form of a pressure for adesired functional state of the hydrodynamic clutch with the controldevice 8, especially the pressure balance 10. Said arrangement isadvantageous in that the device is only active in operation, andtherefore, no cooling oil is lost while driving. Furthermore, it ispossible to make the configuration described in FIG. 1 d highlycost-effective.

The pressure control of the hydrodynamic clutch is configured such thatin operation, the drive unit is lubricated directly from the sump 6,because that is where the coldest operating material is available. Theoperating material flows from the operating material source 6 to thecontrol where a small amount is branched off for compensating leakages,while the main portion of the lubrication 15 flows into the drive unit.

The control device, especially the pressure balance, and the valvedevices that are coupled to or integrated with the pressure balance in aunit, can vary with regard to the chambers formed in the control boring,the control edges of the control plunger and the assignment of theconnections. However, it is relevant that the four basic functionalstates of the control of the hydrodynamic clutch are achieved, where atleast in the controlled state a stepwise and advantageously a continuoustransition is achieved between the individual basic functional states.

FIGS. 6 and 7 illustrate by means of a section of the pressure balance10 the options of arranging individual valve devices, such as VLB1 andVLB2 and the volume controller VLB in the control boring 57. While FIG.6 a reflects the arrangement of the valve devices VLB1 and VLB2 in thecontrol boring 57 by means of a section of the pressure balance 10, FIG.6 b shows an embodiment of the control plunger 49, which is comprised oftwo parts, in addition to the arrangement of the volume controller VLBin the control boring 57.

In contrast, FIG. 7 a shows the arrangement of the back-pressure valvesR1, R2 and R5 in the control plunger 49 for an embodiment according toFIG. 6 a, and FIG. 7 b shows the arrangement for an embodiment of thecontrol plunger 49 according to FIG. 6 b. Said arrangement is such thatthe back-pressure valve devices can influence the cross-sections of thelines as shown under FIG. 1, i.e. they are assigned to the respectivelines.

FIG. 8 illustrates a simplified lubricant or operating material supplysystem 4.8 by means of an illustration according to FIG. 1 a for a driveunit 100.8. The fundamental principle of supplying the hydrodynamicelement 2.8 in the form of the hydrodynamic clutch 5.8 corresponds tothat described in FIG. 1. Therefore, the same identifications are usedfor identical elements. The lubricant or operating material supplysystem 4.8 comprises an operating material source 6.8, in the presentcase in the form of an oil sump, in the present case a sealable oil sumpfrom which by means of a pumping device, in the present case the gearpump 7.8, the oil is to the respective line systems for supplying theindividual elements—the hydrodynamic clutch 5.8 and/or the drive unit100.

According to the invention, a control device 8.8 is assigned to thehydrodynamic clutch 5.8 which, in addition to controlling a variablecharacterizing at least indirectly the functional state of thehydrodynamic clutch 5.8, advantageously the fill factor, realizes orcontrols various supply functions, for example controlling or supplyingthe bridging clutch and supplying the complete drive unit 100 withlubricant. The control device 8.8 for controlling a variablecharacterizing at least indirectly the functional state of thehydrodynamic clutch 5.8 is embodied by a pressure balance 10.8. Thefunctional principle is based on compensating the force of pressureacting on a plunger of a known cross-sectional area or the sealingliquid in a ring pipe by means of a counter-force where a balance offorces is achieved by moving the plunger, for example. A set variablecan be preset for a variable characterizing at least indirectly thefunctional state of the hydrodynamic clutch, which serves as inputvariable of a control device 8.8 assigned to the associated lubricant oroperating material supply system 4.8 for controlling an adjustmentdevice for influencing the operating material supply of the hydrodynamicclutch 5.8 and the lubricant supply of the complete drive unit 100.

The set variable for actuating the adjustment device is then generatedfrom the set value of the variable characterizing at least indirectlythe functional state of the hydrodynamic clutch in dependence of avariable characterizing at least indirectly the pressure in a dischargeline 32.8 of the hydrodynamic clutch 5.8.

Via the pressure balance 10.8, at least three, advantageously four basicfunctional states of the hydrodynamic clutch 5.8 can be set, butadvantageously the adjustment is continuous. Please see FIGS. 3 and 4for the construction of the pressure balance 10.8.

In a first functional state of the hydrodynamic clutch 5.8, operatingmaterial is supplied from the operating material source 6.8 via acooling device 11.8 into the lubricant system 9.8. Said functional stateis illustrated in FIG. 9 a by means of a section of the hydraulicsdrawing according to FIG. 8. The operating material, for which oil isused above all, flows from the oil sump 6.8 via line 13.8 into theadjoining line section 14.8, the cooling device 11.8 and line 18.8 intothe lubricant line 15.8 which is coupled to the lubricant connections ofthe lubricant supply system 9.8 of the drive unit 100.8. In saidfunctional state the hydrodynamic clutch 5.8 is completely empty, and nooperating material is supplied to the toroidal working space. Thedisengaged state of the hydrodynamic clutch 5.8 corresponds to the firstfunctional state. In said state, no torque is transmitted, and theoperating material is required merely for lubricating the individualelements of the drive unit 100.8. In the lubricant line 15.8, aback-pressure valve R5 is advantageously disposed so as to prevent thatthe operating material flows back from the lubricant line 15.8.

The lubricant and operating material supply system 4.8 commonly used bythe drive unit 100.8, i.e. by the hydrodynamic clutch 5.8 and thebridging clutch 3.8, also supplies the bridging clutch 3.8 with therequired control pressure. In the illustrated case, under FIG. 1 a, thesupply line 25.8 is coupled directly to the principal supply line 26.8that connects the pumping device, in the present case, the gear pump7.7, with line 13.8.

The state of putting the hydrodynamic clutch 5.8 into operation, theso-called filling phase, can be described by the line connections forthe operating position 1 illustrated or realized in FIG. 9 a by means ofthe pressure balance 10.8. The filling process substantially takes placevia the oil sump 6.8 which can be coupled via a line 14.8 to the supplyline 30.8 by means of the pressure balance 10.8. The line 14.8 isadvantageously provided with a pressure control valve VLP.

The operating material flows via the principal line 26.8 into theconnecting line 13.8 to line 14.8. The operating material then flows vialine 14.8, the coupling between line 14.8 and line 20.8, which iscoupled to the supply line 30.8 of the hydrodynamic clutch, into thehydrodynamic clutch 5.8. As a result of the pressure differences arisingin the hydrodynamic clutch 5.8 operating material enters line 21.8 viathe discharge line 32.8 and is supplied as a result of the position orpositions of the pressure balance 10.8 characterizing said functionalstate into the connecting line to the cooler 11.8 and via said coolerback into line 14.8 so as to be resupplied to the hydrodynamic clutch 2.Therefore, during the filling phase a closed cooling circuit is alreadyformed between the discharge line 32.8 of the hydrodynamic clutch 5.8and the supply line 30.8. Said closed circuit can also be called coolingcircuit and is identified by 33.8.

A further third functional state of the hydrodynamic clutch 5.8 can bedescribed by the position of the pressure balance 10.8 and theconnections thus realized between the individual lines as illustrated inFIG. 9 c. Said functional state describes the controlled state of thehydrodynamic clutch 5.8. The lines 14.8 and 20.8 are coupled togetherand thus to the supply line 30.8 of the hydrodynamic clutch 5.8. Thepressure in the channel 14.8 approximates the inflow resistance in line20.8. The pumping device in the form of the gear pump 7.8 merelyresupplies the leakage amount of the hydrodynamic clutch. Excessoperating material supplied by the pumping device, especially the gearpump 7.8, flows from line 14.8 into the lubricant line 15.8 or back intothe sealable sump 6.8. Because of the pressure differences arising inthe clutch 5.8, a cooling circuit 33.8 is also generated in this case,where the coolant flows from the discharge line 32.8 into the connectingline 18.8 to the cooling device 11.8 and after passing the coolingdevice 11.8 it is supplied to the supply line 14.8 and into the supplyline 30.8 of the hydrodynamic clutch. Any excess operating material isreturned to the sump 6.8 via line 19.8. Said third functional state,which corresponds to the operating position 2 in FIG. 8, can be furtherdivided into a fourth functional state which is required for settingvery low pressures, i.e. for generating a low transmission moment, whichcorresponds to the operating position 3 of the pressure balance 10.8 andwhich is illustrated in FIG. 9 d. In said functional state, the supplypressure is lowered.

With regard to the individual positions of the control valve of thepressure balance 10 for realizing the individual functional states,please see FIGS. 4 a to 4 d.

1. A method for controlling the filling process of a hydrodynamic clutch(2) from an associated lubricant or operating material supply system(4), comprising at least one operating material source (6), a coolingdevice (11), where the hydrodynamic clutch comprises at least two bladewheels that together form a toroidal working space, to which at leastone supply line (30) and one discharge line (32) are assigned; themethod comprising: presetting a set variable for a variablecharacterizing at least indirectly the functional state of thehydrodynamic clutch (2), which serves as an input variable of a controldevice (8) assigned to the associated lubricant and operating materialsupply system (4) comprising a pressure balance that controls anadjustment device for influencing the operating material supply of thehydrodynamic clutch (2) such that at least three basic functional statesof he hydrodynamic clutch (2) can be set, where the set variable foractuating the adjustment device is generated from the set value of thevariable characterizing at least indirectly the functional state of thehydrodynamic clutch (2) in dependence of a variable characterizing atleast indirectly the pressure in the discharge line (32) of thehydrodynamic clutch (2), and in a first functional state, thehydrodynamic clutch (2) is empty, in a second basic functional state ofthe hydrodynamic clutch (2) supplying the working space of thehydrodynamic clutch (2) with operating material from the operatingmaterial source (6), and in a closed circuit, resupplying operatingmaterial from the working space to the working space via the coolingdevice (11).
 2. Method as defined in claim 1, where the lubricant oroperating material supply system (4) further comprises a reservoir (27)characterize in that in the second and third basic functional states theworking space of the hydrodynamic clutch (2) is additionally suppliedwith operating material from the reservoir (27).
 3. Method as defined inclaim 1, characterized in that at least in the third basic functionalstate the change in the pressure in the discharge line (32) to theworking space can be set so as to be continuous.
 4. Method as defined inclaim 1, characterized in that the transition between the individualfunctional states can be set so as to be continuous.
 5. Method asdefined in claim 1, characterized by the following features: thehydrodynamic clutch being a component of a drive unit with a bridgingclutch (3) and a common lubricant or operating material supply system(4) is assigned to the hydrodynamic clutch (2) and the bridging clutch(3); where in a basic functional state of the hydrodynamic clutch asupply of the lubricant system for the drive unit can be additionallyset; where in the first functional state of the hydrodynamic clutchoperating material from the operating material source(6) is supplied tothe lubricant connection (15) of the drive unit via the cooling device(11).
 6. Method as defined in claim 5, characterized in that the supplyof the hydrodynamic clutch (2) with operating material takes priorityover the supply of the complete drive unit with lubricant.
 7. Thecombination comprising: a control device for influencing the functionalstate of a hydrodynamic clutch (2) with an associated lubricant andoperating material supply system (4), comprising at least one operatingmaterial source (6), a cooling device (11), the hydrodynamic clutch (2)comprising at least two blade wheels that together form a toroidalworking space and one supply line (30) and one discharge line (32); thecontrol device (8) with at least one input for a variable characterizingat least indirectly a set functional state and a plurality of outputs;the outputs being coupled to means for influencing the supply line (30)and/or the discharge line (32) of the hydrodynamic clutch; means forinfluencing the supply from an operating material source (6) and/or forrealizing an operating material circulation in a closed circuit from thehydrodynamic clutch (2); the control device (8) comprising a pressurebalance (10); the pressure balance (10) being provided with at least onecontrol boring (57); the control boring (57) connected at leastindirectly at least to the following connections: supply (30) of thehydrodynamic clutch (2) discharge (32) of the hydrodynamic clutch (2)operating material supply source (6) the pressure balance (10) furtherprovided with at least one control plunger (49) guided in the controlboring (57) while at least partially releasing and/or locking thecoupling with the connections, where the control plunger (49) can beactuated by a force of pressure which is at least proportional to thevariable characterizing at least indirectly the set functional state anda counter-force characterized by the pressure in the discharge line (32)of the hydrodynamic clutch (2), where a balance of forces is achieved bymeans of moving the control plunger (49).
 8. The combination as definedin claim 7, characterized in that the control boring (57) is connectedto connections for the lines (18, 14) of a closed hydrodynamic circuit(33) assigned to the working space of the hydrodynamic clutch (2). 9.The combination as defined in claim 7, wherein: the outputs are formedby the connections (20, 19, 14, 16); the means for influencing thesupply and/or discharge (30, 32) of the hydrodynamic clutch (2) areformed by the pressure balance (10).
 10. The combination as defined inclaim 7, characterized in that the input of the pressure balance (10)for a variable characterizing at least indirectly the functional stateof the hydrodynamic clutch (2) is formed by a hydraulic connection forforming a force of pressure on a plunger area of the control plunger(57).
 11. The combination as defined in claim 10, characterized in thatinput of the pressure balance (10) is coupled to a proportional valve(70) serving as a device for presetting a set functional state.
 12. Thecombination as defined in claim 7, characterized in that for presettingthe set functional state the control plunger (49) can be actuated bymeans of an electromagnetically generated force.
 13. The combination asdefined in claim 7, characterized in that for presetting the setfunctional state the control plunger (49) can be actuated by means of amechanically generated force.
 14. The combination as defined in claim 7,characterized in that the control plunger (49) comprises at least twopartial elements (49.1, 49.2) which can be firmly connected.
 15. Thecombination as defined in claim 7, characterized by the followingfeatures: the hydrodynamic clutch (2) is a component of a drive unitcomprising a bridging clutch; the lubricant and operating materialsupply system (4) assigned to the hydrodynamic clutch (2) is alsoassigned to the bridging clutch; the outputs of the control device (8)are coupled to means for influencing the lines (15) of the lubricantsupply system (9) of the drive unit (100).
 16. The combination asdefined in claim 7, characterized in that the control boring (57) iscoupled to a lubricant supply line (15).
 17. The combination as definedin claim 16, characterized in that for realizing a continuous lubricantsupply at least on volume control valve (VLB) is provided between theconnections of the lubricant supply line (15) and the supply (30) to thehydrodynamic clutch (2) in the control boring (57).
 18. The combinationas defined in claim 16, characterized in that for realizing a continuouslubricant supply at least two valve devices (VLB1, VLB2) that areactuated in dependence of the pressure are provide in the control boring(57) where via a first valve device (VLB1) the coupling between theoperating material supply source (6) and the supply (30) of thehydrodynamic clutch 2) is produced and via a second said valve device(VLB2) the coupling between the operating material supply source (6) andthe lubricant supply system (9) of the drive unit is produced.
 19. Thecombination as defined in claim 18, characterized in that the two valvedevices (VLB1, VLB2) for realizing a continuous lubricant supply whichare actuated in dependence of the pressure and/or the back-pressurevalve devices (R1, R5) that are disposed in the control boring (57) andthe valve device (R2) are combined into one valve unit.
 20. Thecombination as defined in claim 7 for a drive system with a storagedevice (27), wherein: the pressure balance is provided with a connection(19) which is connected to a storage device and which can be coupled tothe supply (30) of the hydrodynamic clutch (2) by means of moving thecontrol plunger (57); a valve device (R2) is assigned to storage deviceconnection (19) for preventing a back flow of the operating materialfrom the hydrodynamic element.
 21. Control The combination as defined inclaim 20, wherein: the storage device (27) is connected to the lubricantsupply line (15) by a connecting line means and the connecting linemeans are provided for preventing that the stored volume is pushed outinto the lubricant supply line (15); said means for preventing comprisetwo back-pressure valve devices (R1, R5).
 22. The combination as definedin claim 21, characterized in that the valve device (R2) and theback-pressure valve devices (R1, R5) are disposed in the control boring(57) of the pressure balance (10).